December 2012
Intermediate to advanced
320 pages
9h 35m
English
A Second Drive for Elevator Door Movement |
Don Harvey |
The Technical Brief article “An Elevator Door Hinge” describes one way to link two flats so they will move like the paired panels of an elevator door. Because that drive is made up of rigid lever-arms it takes up a fair amount of space beside the frame of the door opening. Whenever enough clear space isn’t available the sheave-and-cable alternative presented here can be used instead.
Figures 1A and 1B illustrate the drive, which uses a principle of double-purchase rigging to move one panel twice as far as another within a given time. To avoid clutter, the illustrations show only the drive’s components.
FIGURES 1A & 1B: REAR VIEW
FIGURE 2: SCHEMATIC OF REVEFSE AND REPEAT ADDITION
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